A liquid crystal display device or an organic electroluminescence display device (hereinafter, referred to as an “organic EL display device”) includes a plurality of pixels each including a display element such as a liquid crystal element or a light emitting element, and provides an image by controlling the driving of each of the pixels.
The organic EL display device includes a plurality of pixels provided on a substrate, and the plurality of pixels each include a plurality of transistors and an organic light emitting element (hereinafter, referred to as a “light emitting element”). The light emitting element include a pair of electrodes and a layer containing an organic compound. The layer is provided between the pair of electrodes. The light emitting element is a self-light emitting element that is driven by an electric current provided between the pair of electrodes. The supply of the electric current to the light emitting element is controlled by the transistors, and thus the display device displays a video. Such an EL display device is suitable as a flexible and thin display device because, for example, the light emitting element included in the organic EL display device has a stack structure including thin organic films, and the organic EL display device does not need a backlight unit. Using these features of the organic EL display device, a so-called flexible display (sheet display) including a flexible substrate and a light emitting element provided thereon is now produced. For example, Japanese Laid-Open Patent Publication No. 2008-111890 discloses a flexible organic EL display device having a structure in which the size of, the pitch between, pixels are varied in order to suppress distortion of the screen when the flexible organic EL display device is folded.